Used my old smog machine of 30 years, to check for head gasket leaks into the cooling system. This machine is super sensitive to exhaust emissions. Although I had to do a lot of repair work to the machine first. Now it runs great.

The MT2500 Scanner made it obvious that the O2 sensor was bad. I'll double check the sensor wiring too make sure.

The XJ overheats easily. Engine compartment is coated in rust. I'll probably rod out the radiator.

Here is the video I shot of sniffing the overflow tank, and shooting temps of the radiator tanks.

my guess is that engine needs a good flush and maybe a radiator. you got some boiling coolant

For certain! Didn't help unfortunately.

Today I got about 60% through rodding out the radiator. At least 10% of the tubes were plugged, so far. I think it's the original 1988 radiator as it's all brass with plastic tanks. The bottom 1.5 inches of the center section was covered in debris that might block some air flow. I'll put in a new thermostat too since it's far easier to do with the radiator out of the vehicle. Probably should inspect the water pump too.

Started rodding out the radiator of the XJ. About half way through the entire process. Here are a couple of videos of some the work. Not sure if the theory I mention in the beginning of video 1, 'holds water'.

Next step is to replace the water pump, while it's easily accessible. It looks like cast iron so it might be original like the heater hoses are. New pump is in house already. Along with a new thermostat and housing with petcock valve.

The new gaskets for the radiator tanks are far too thin and a slightly different shape, although still rectangular. Vendor is checking stock for a fatter wall gasket. The trans cooler gaskets look right. Can't wait to have a radiator with a cap on it!! Also have new trans lines to replace seriously weather checked ones.

The tool to compress the spring at the top of the steering column arrived today. Also had to order the turn signal stalk. Half of it was broken off with wires hanging out. Can't wait to get this the column fully re-assembled !!!

Took yesterday off and looked at a semi local XJ for sale. No title and complicated too. Nice shape. Disassembled motor still in chassis. Very long shot.

Been dying to get the radiator back together. Gaskets from a CA vendor both times don't match the original. So more searching. Backup plan is to re-use the original gasket with 500 degree silicone to seal it all up.

New water pump, thermostat with bleed port, and thermostat housing with petcock valve are now installed.

Once this beater is assembled and running again, testing for overheating and driveability will make the jeep ready for engine teardown to locate the source of the engine noise.

Talked to another radiator shop and the guy said if you can't get the right gasket, just use silicone. I've got 500 degree silicone. I recon that's where I'm going.

The radiator is the only part missing for a running vehicle. In the a.m., I'll try and get the tank mounted to the radiator. The silicone only says 15 minutes of working time. Then 24 hours of cure time. So pressure testing the radiator won't occur for 24.25 hours after assembly. Sigh.

Found the track rod end is sloppy today, because the steering works so well now. One of those next weak link things. Nice to have a new turn signal stalk.

Once all of this is done, we want to drive the old girl around for a couple of days to check for overheating. Then pull it into the garage to take the valve cover, head, and oil pan off to find out what's making so much racket.

The radiator supply shop in SoCal was on the phone with me probably an hour yesterday. The tank that holds the transmission cooler, has 3 different sized gaskets, it turns out. Basically, 3 flat o-rings you might say. One of them they sent me already. The other two they don't carry and can't get.

So I ordered a small sheet of 1/16 thick high temp silicone gasket material to cut new gaskets from. It won't get here for a week.

The tank gasket that looks like a giant o-ring, isn't available either. Another shop told me they just use silicone to seal the old gasket with. So I will, with 500 degree silicone that's already here.

If I can find some large rod or tubing I'll make some punches to cut out the gaskets. I get the feeling this won't be my only XJ.

I sure enjoy doing projects like this. This one is just taking longer.